Study On The Effective Separation And Fine Processing Of Magnesium From Boron Slurry

Boron slurry is the solid waste of boron industry, which not only engrosses a great deal of the soil, but also cause hazard to field, groundwater and Atmospheric Environment. About 40 wt% Magnesium Oxide in the boron slurry, which is discharged freely causes Magnesium resource waste greatly. So looking for suitable method for recycling Magnesium, it is not only can gain tremendous economic benefit, but also can improve ecological environment and speed up sustainable development process.At present, the main method for leaching Magnesium from boron slurry is acid leaching. In the course, iron and aluminium impurities dissolve into the leaching liquor, which effects the leaching liquor purity and further use, and should be removed. Traditional method for purification uses Alkali. According to the leaching liquor being acid solution system, The test put forward solid extraction mothod for separating iron and aluminium impuritiesunder under this circumstance. This method has many advantages such as no magnesium loss, renewable recycling use, rapid separation and high efficiency. Subsequently, fine processing of leaching liquor is researched and morphology-homogeneous magnesium hydroxide sulfate whiskers are received, which can be used for Enhancement and flame retardant. The concrete research contents are as follows:1.Study on leaching magnesium from the boron slurry is described. We use hydrochloric acid and sulfuric acid as leaching agent to study the soaking rate of Mg from the boron slurry. The results show that sulfuric acid has higher Mg leaching rate and lower cost comparing with hydrochloric acid. The optimum condition of sulfuric acid leaching is concluded as follow: Using 10 g drying boron slurry as our initial state, the dosage of H2SO4 is 7.92 ml which the dilution rate is 1:3(120 % of the theoretical dosage of H2SO4), reactive time is 80min, reactive temperature is 70℃, the Mg leaching rate receives 94.2%.2.According to the leaching liquor being acid solution system, We use solvent extraction and solid extraction method for purification reseach, the technical parameters and influencing factors of the solvent extraction technique have been studied. At last, we separate iron and aluminium with self-made solid extraction adsorption column, the technical parameters, the stability and regrowth of the extraction adsorption columnand also have been studied. After solid extraction, The isolation rates of iron and aluminium impurities receive 99.7 % and 99.0 % respectivly. Refined magnesium sulfate solution is received and the magnesium from the boron slurry is separated effectively.3.Preparation of magnesium hydroxide sulfate hydrate whiskers is researched. Using Sodium Hydroxide as precipitant, fine processing of magnesium salt is researched and sector shape 152 model magnesium hydroxide sulfate hydrate whiskers are received by hydrothermal method. The hydrothermal influence factors such as concentration, filling degree, reaction temperature and time have been discussed. The optimum condition of synthesizing is concluded as follow: the concentration of MgSO₄ is 0.5-0.8 mol/L, molar ratio of MgSO₄ and Mg(OH)₂ is 2:1, filling degree is more than 32 %, stirring rate is 600 r/min and reaction temperature and time are 140℃and 4 h respectively.